Diamond identification apparatus

ABSTRACT

A diamond identification apparatus is disclosed, the diamond identification apparatus comprising a support platform for receiving a gemstone at an observation position, a first light source arranged to emit light at a predetermined angle towards the observation position and a first photodiode arranged to detect an amount of light from the first light source being reflected from the gemstone at the observation position. The diamond identification apparatus further comprises a second light source arranged to emit light towards the observation position, a second photodiode arranged to detect light from the second light source that passes through the gemstone at the observation position and a processor unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/751,529, filed on Feb. 9, 2018, which is a National Stage Entry ofPCT International Application No. PCT/IB2016/054071, with aninternational filing date of Jul. 7, 2016, which claims priority toSingapore Patent Application No. 10201506282W, filed Aug. 12, 2015, thedisclosures of which are incorporated herein by this reference in theirentireties.

TECHNICAL FIELD

The following is in the field of gemology, and discloses an apparatuscapable of determining whether a gemstone is a diamond and thendetermining whether the diamond is natural or possibly synthetic.

BACKGROUND ART

To the naked eye it is sometimes difficult for the general public oreven trained gemologists to determine whether a gemstone is a diamond ora diamond simulant (for example a synthetic moissanite or a cubiczirconia). Gemologists therefore rely on gemstone identification devicesto identify the type of the gemstone. Some gemstone identificationdevices work on the principle of measuring the reflectivity of thegemstone. Each type of gemstone would reflect light in differentamounts. Visible or infrared light is shown onto the gemstone and theamount of reflected light is measured by a photodetector or photodiode.The measured light is cross-referenced to a table or chart and the typeof the gemstone is determined.

If the type of the gemstone is determined to be a diamond, thegemologist would then usually want to know if the diamond is natural orsynthetic. Gemologists would usually use a detector device to shineultraviolet light on the diamond. These detector devices work bymeasuring the permissibility of ultraviolet light through the diamond.If the diamond does not permit any ultraviolet light through, thediamond is inferred to be natural. If the diamond permits ultravioletlight through, there is a high possibility that the diamond issynthetic.

However, the two aforementioned devices usually exist as separatedevices. This means that a gemologist would have to carry multipledevices around which can be very cumbersome. There does not exist in theart a single device that integrates the functionalities of theaforementioned devices in a portable and convenient manner.

Thus, there is a want for an apparatus or device which is capable ofdetermining whether a gemstone is a diamond and then determining whetherthe diamond is natural or possibly synthetic.

Furthermore, other desirable features and characteristics will becomeapparent from the subsequent detailed description and the appendedclaims, taken in conjunction with the accompanying drawings and thisbackground of the disclosure.

SUMMARY OF INVENTION

According to an aspect of the invention, a diamond identificationapparatus is disclosed, the diamond identification apparatus comprisinga support platform for receiving a gemstone at an observation position,a first light source arranged to emit light at a predetermined angletowards the observation position and a first photodiode arranged todetect an amount of light from the first light source being reflectedfrom the gemstone at the observation position. The diamondidentification apparatus further comprises a second light sourcearranged to emit light towards the observation position, a secondphotodiode arranged to detect light from the second light source thatpasses through the gemstone at the observation position and a processorunit. Wherein the processor unit is configured to determine that thegemstone is a diamond in response to the amount of light detected by thefirst photodiode, and if the gemstone is determined to be a diamond,then determine that the diamond is natural in response to the secondphotodiode not detecting light.

Preferably, the processor unit is further configured to determine thatthe diamond is possibly synthetic in response to the second photodiodedetecting light.

Preferably, the processor unit determines that the gemstone is a diamondby calculating a reflectivity value in response to the amount of lightdetected by the first photodiode, and cross-referencing the reflectivityvalue with reference data.

Preferably, the reflectivity value is substantially 17.1%, orsubstantially 19%, or within the range of 17.1% and 19%.

Preferably, the second photodiode has a horizontal axis and a verticalaxis, and wherein the first light source and the first photodiode arearranged such that the first light source and the first photodiode liesubstantially along the horizontal axis of the second photodiode andsandwich the second photodiode, and the first light source and the firstphotodiode do not lie substantially along the vertical axis of thesecond photodiode.

Preferably, the first light source, the first photodiode and the secondphotodiode form part of a sensor module.

Preferably, the support platform defines an opening for receiving thegemstone at the observation position.

Preferably, the opening of the support platform and the second lightsource are arranged to lie substantially along the vertical axis of thesecond photodiode.

Preferably, the light emitted by the first light source is visible orinfrared light.

Preferably, the light emitted by the second light source is ultravioletlight.

Preferably, the ultraviolet light emitted by the second light source hasa wavelength of less than 370 nanometers.

Preferably, the first photodiode is oriented towards the observationposition at substantially the predetermined angle.

Preferably, the predetermined angle is between 30° to 60°.

Preferably, the diamond identification apparatus further comprises amemory module and the memory module stores the reference data.

Preferably, the diamond identification apparatus further comprises adisplay module, and wherein the determination by the processor unit thatthe gemstone is a diamond, and the determination by the processor unitthat the diamond is natural or possibly synthetic, are displayed on thedisplay module.

Preferably, the diamond identification apparatus further comprises ahousing for encapsulating the support platform, the first light source,the first photodiode, the second light source and the second photodiode,and the housing comprises a window which can be opened to insert orremove the gemstone.

According to another aspect of the invention, a sensor module for use ina diamond identification apparatus is described, the diamondidentification apparatus comprising a processor unit, a support platformfor receiving a gemstone at an observation position and a second lightsource arranged to emit light towards the observation position. Thesensor module comprises a first light source arranged to emit light at apredetermined angle towards the observation position, a first photodiodearranged to detect an amount of light from the first light source beingreflected from the gemstone at the observation position, and a secondphotodiode arranged to detect light from the second light source thatpasses through the gemstone at the observation position. Wherein theprocessor unit is configured to determine that the gemstone is a diamondin response to the amount of light detected by the first photodiode, andif the gemstone is determined to be a diamond, then determine that thediamond is natural in response to the second photodiode not detectinglight.

Preferably, the second photodiode detects light and the processor unitdetermines that the diamond is possibly synthetic.

Preferably, the second photodiode has a horizontal axis and a verticalaxis; and wherein the first light source and the first photodiode arearranged such that the first light source and the first photodiode liesubstantially along the horizontal axis of the second photodiode andsandwich the second photodiode, and the first light source and the firstphotodiode do not lie substantially along the vertical axis of thesecond photodiode.

Preferably, the light emitted by the first light source is visible orinfrared light.

Preferably, the first photodiode is oriented towards the observationposition at substantially the predetermined angle.

Preferably, the predetermined angle is between 30° to 60°.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separate viewsand which together with the detailed description below are incorporatedin and form part of the specification, serve to illustrate variousembodiments, by way of example only, and to explain various principlesand advantages in accordance with a present embodiment.

FIG. 1 shows a schematic diagram of an apparatus in accordance with anembodiment of the invention.

FIG. 2 shows a flowchart depicting the steps taken by an apparatus todetermine the type of the gemstone and if the type of the gemstone isdetermined to be diamond, then determine whether the diamond is naturalor possibly synthetic, in accordance with an embodiment of theinvention.

FIG. 3 shows a schematic diagram of an apparatus in operation todetermine the type of a gemstone, in accordance with an embodiment ofthe invention.

FIG. 4 illustrates an exemplary method to cross-reference the calculatedreflectivity value with the reference data to determine the type of thegemstone.

FIG. 5 shows a schematic diagram of an apparatus in operation todetermine if the diamond is natural or possibly synthetic, in accordancewith an embodiment of the invention. FIG. 6 shows a further embodiment,which is similar to the embodiment of FIG. 3, and FIG. 7 shows a furtherembodiment, which is similar to the embodiment of FIG. 5.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendepicted to scale. For example, the dimensions of some of the elementsin the block diagrams or steps in the flowcharts may be exaggerated inrespect to other elements to help improve understanding of the presentembodiment.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and isnot intended to limit the invention or the application and uses of theinvention. Furthermore, there is no intention to be bound by any theorypresented in the preceding background of the invention or the followingdetailed description. It is the intent of the preferred embodiments todisclose an apparatus or device which is capable of determining whethera gemstone is a diamond and then determining whether the diamond isnatural or possibly synthetic. These two steps usually occur insuccession. Once a gemologist has determined that a gemstone is adiamond, logically, the gemologist would then want to know if thediamond is natural or possibly synthetic. Therefore, the disclosedapparatus is advantageous as it teaches a single apparatus capable ofperforming both these logically ensuing steps. Therefore, it is moreconvenient for the gemologist to carry around a single device with thecombined functionalities as opposed to multiple devices.

FIG. 1 shows a schematic diagram of apparatus 100 in accordance with anembodiment of the invention. Apparatus 100 comprises first light source101, first photodiode 102 and second photodiode 103. Preferably, firstlight source 101, first photodiode 102 and second photodiode 103 formpart of a sensor module 104.

Second photodiode 103 has a horizontal axis X-X and a Vertical axis Y-Y.Preferably, the arrangement is such that first light source 101 andfirst photodiode 102 lie substantially along the horizontal axis X-X.Preferably, first light source 101 and first photodiode 102 sandwichsecond photodiode 103, such that second photodiode 103 lies intermediatebetween first light source 101 and first photodiode 102. In other words,first light source 101 lies on one side of vertical axis Y-Y while firstphotodiode 102 lies on the other side of vertical axis Y-Y. Preferably,first light source 101 and first photodiode 102 do not lie substantiallyalong the vertical axis Y-Y as shown in FIG. 1. This is so that firstlight source 101 and first photodiode 102 do not obstruct any lightwhich is to be detected by second photodiode 103.

Apparatus 100 further comprises support platform 105 and a second lightsource 106. Preferably, support platform 105 has a bank 107 whichdefines an opening 108. Preferably, opening 108 has a circular profile.Preferably, opening 108 has a width or diameter smaller than the tablesize of a gemstone. Preferably, opening 108 has a width or diameter of 1millimeter (mm). When apparatus 100 is in operation, the gemstone ispreferably placed on support platform 105. More particularly, thegemstone is preferably placed over opening 108, with portions of thegemstone contacting bank 107 for support. Preferably, the table portionof the gemstone is placed over opening 108 and rests on bank 107. Thisis the observation position of the gemstone. Preferably, opening 108 ofsupport platform 105 lies substantially along vertical axis Y-Y ofsecond photodiode 103.

Preferably, first light source 101 emits visible light or infraredlight. Preferably, first light source 101 is arranged so as to emitlight at a predetermined angle towards the observation position.Preferably, first light source 101 is orientated towards the observationposition at a predetermined angle. Preferably, the predetermined angleis an acute angle between 30° to 60°. Preferably, the predeterminedangle is substantially 45°. In operation, when the gemstone is placed atthe observation position, the light from first light source 101 willreflect off the gemstone.

First photodiode 102 is arranged to detect the amount of visible lightor infrared light emitted from first light source 101 being reflectedfrom the gemstone placed at the observation position. Preferably, firstphotodiode 102 is a visible light or infrared light detector.Preferably, first photodiode 102 is arranged to be at the optimalposition to detect the amount of visible light or infrared light emittedfrom first light source 101 being reflected from the gemstone placed atthe observation position. Preferably, first photodiode 102 is arrangedsuch that it is orientated towards the observation position. Preferably,first photodiode 102 is orientated towards the observation position atsubstantially the same predetermined angle as first light source 101.

Preferably, second light source 106 is arranged to be substantiallyperpendicular to support platform 105. Preferably, second light source106 is arranged to be above support platform 105. Preferably, secondlight source 106 is arranged to lie substantially along vertical axisY-Y of second photodiode 103. Preferably, second light source 106 emitsultraviolet light. Preferably, second light source 106 emits ultravioletlight with a wavelength of less than 370 nanometers (nm). Preferably,second light source 106 is arranged to emit ultraviolet light towardsthe observation position.

In operation, second photodiode 103 is arranged to detect theultraviolet light emitted from second light source 106 that passesthrough the gemstone at the observation position. Preferably, secondphotodiode 103 is an ultraviolet light detector. Preferably, secondphotodiode 103 is substantially vertically aligned with second lightsource 106 and the gemstone at the observation position. As first lightsource 101 and first photodiode 102 are arranged to not liesubstantially along vertical axis Y-Y of second photodiode 103,ultraviolet light emitted from second light source 106 can travelthrough gemstone at the observation position, and towards secondphotodiode 103 unobstructed. Preferably, second photodiode 103 isconnected to vertical chamber 109 so that the ultraviolet light emittedfrom second light source 106 can be funneled unhindered towards secondphotodiode 103.

Apparatus 100 comprises processor unit 110. Preferably, processor unit110 comprises a computer, a microcontroller, a microprocessor or aprocessor. Preferably, processor unit 110 can obtain readings from firstphotodiode 102 and second photodiode 103. Preferably, the readings fromfirst photodiode 102 are the amount of detected reflected light.Preferably, the readings from second photodiode 103 are whether or notultraviolet light has been detected. Preferably, apparatus 100 comprisesthe necessary electrical wiring between first photodiode 102, secondphotodiode 103 and processor unit 110 (as shown in FIG. 1). Preferably,processor unit 110 can send the necessary instructions to activate,deactivate and regulate first light source 101 and second light source106.

Preferably, apparatus 100 comprises memory module 111 to store thereadings from first photodiode 102 and second photodiode 103.Preferably, memory module 111 stores reference data. Preferably, thereference data contain a plurality of gemstone types and theircorresponding reflectivity values.

Preferably, apparatus 100 comprises display module 112. Preferably,display module 112 can comprise a liquid crystal display (LCD).Preferably, processor unit 110 can display on display module 112 theresults of the determination e.g. that the gemstone is a diamond, thatthe diamond is natural or that the diamond is possibly synthetic.Preferably, display module 112 has touch screen capability and canaccept user input.

Preferably, apparatus 100 comprises a power supply module (not shown inFIG. 1) to provide power to first light source 101, second light source106, first photodiode 102, second photodiode 103, processing unit 110,memory module 111 and display module 112.

Preferably, apparatus 100 also has a housing (not shown in FIG. 1) whichsubstantially encapsulates support platform 105, first light source 101,second light source 106, first photodiode 102 and second photodiode 103.Preferably, the housing has a window which can be opened to insert orremove the gemstone. Preferably, the housing has buttons which cantrigger processor unit 110 to execute actions.

FIG. 2 shows a flowchart depicting the steps taken by apparatus 100 todetermine the type of the gemstone and if the type of the gemstone isdetermined to be diamond, then determine whether the diamond is naturalor possibly synthetic, in accordance with an embodiment of theinvention. FIG. 3 shows a schematic diagram of apparatus 100 inoperation to determine the type of the gemstone, in accordance with anembodiment of the invention. Gemstone 301 is placed at the observationposition on support platform 105. Preferably, the table portion ofgemstone 301 is placed over opening 108 and rests on bank 107. (see FIG.3). This orientation of gemstone 301 is ideal as the table portion ofgemstone 301 is substantially flat, which optimizes the reflection oflight (from first light source 101) off gemstone 301 and onto firstphotodiode 102. Preferably, gemstone 301 is colorless. Preferably,gemstone 301 is a colorless diamond graded from D to J.

Now referring to FIG. 2, in step 201, apparatus 100 accepts a user inputwhich initiates the testing procedure. This user input may be via abutton on the housing of apparatus 100 that is depressed or via a touchscreen input on display module 112.

In step 202, processor unit 110 causes first light source 101 to emitvisible light or infrared light towards gemstone 301 at the observationposition. This is illustrated in FIG. 3.

In step 203, first photodiode 102 detects the amount of visible light orinfrared light emitted from first light source 101 reflected fromgemstone 301 at the observation position. This is illustrated in FIG. 3.

In step 204, processor unit 110 obtains from first photodiode 102 theamount of detected reflected light.

In step 205, processor unit 110 calculates a reflectivity value from theamount of detected reflected light and determines the type of gemstone301. The reflectivity value represents the percentage of light beingreflected. A particular type of gemstone would exhibit a range ofreflectivity values. For example, diamond would normally exhibitreflectivity values of between 17.1% and 19%. Preferably, the differenttypes of gemstones and their corresponding reflectivity values will bestored as reference data in memory module 111. Therefore, once thereflectivity value has been calculated, processor unit 110 wouldcross-reference the calculated reflectivity value with the referencedata to determine the type of gemstone 301. An exemplary method tocross-reference the calculated reflectivity value with the referencedata to determine the type of gemstone 301 is illustrated in FIG. 4.

Referring to FIG. 4, processor unit 110 first checks if the reflectivityvalue is larger than 12.5% 401. If the reflectivity value is smallerthan 12.5%, processing unit 110 determines that gemstone 301 is adiamond simulant 402. If the reflectivity value is larger than 12.5%,processor unit 110 then checks to see if the reflectivity value islarger than 14.8% 403. If the reflectivity value is smaller than 14.8%,processor unit 110 determines that gemstone 301 is a cubic zirconia 404.If the reflectivity value is larger than 14.8%, processor unit 110 thenchecks to see if the reflectivity value is smaller than 17.1% 405. Ifthe reflectivity value is smaller than 17.1%, processor unit 110determines that gemstone 301 is a diamond simulant 406. If reflectivityvalue is larger than 17.1%, processor unit 110 then checks to see if thereflectivity value is smaller than 19% 407. If the reflectivity value issmaller than 19%, processor unit 110 determines that gemstone 301 is adiamond 408. If the reflectivity value is larger than 19%, processorunit 110 checks to see if the reflectivity value is smaller than 23.1%409. If the reflectivity value is smaller than 23.1%, processor unit 110determines that gemstone 301 is a synthetic moissanite 411. If thereflectivity value is larger than 23.1%, processor unit 110 determinesthat gemstone 301 is a diamond simulant 410. Preferably, processor unit110 can display on display module 112 the results of the determination.Alternatively, the type of gemstone 301 can be determined by therefractive index. A particular type of gemstone 301 would exhibit aspecific refractive index. Preferably, the refractive index can becalculated from the reflectivity value using the equationx=[(n−1)/(n+1)]², where x is the reflectivity value and n is therefractive index.

Referring back to FIG. 2, in step 206, if processor unit 110 determinesthat gemstone 301 is a diamond, processor unit 110 automatically causessecond light source 106 to emit ultraviolet light towards gemstone 301at the observation position. This is illustrated in FIG. 5. Preferably,processor unit 110 displays on display module 112 the results of thedetermination i.e. that the gemstone is a diamond.

In step 207, processor unit 110 checks whether second photodiode 103 hasdetected any ultraviolet light.

If second photodiode 103 has not detected any ultraviolet light (i.e.gemstone 301 at the observation position did not allow any ultravioletlight through and onto second photodiode 103), in step 208, processorunit 110 determines that gemstone/diamond 301 is natural. Preferably,processor unit 110 displays on display module 112 the results of thedetermination i.e. that the diamond is natural.

If second photodiode 103 has detected ultraviolet light (i.e. gemstone301 at the observation position has allowed ultraviolet light throughand onto second photodiode 103), in step 209, processor unit 110determines that gemstone/diamond 301 is possibly synthetic. The masonwhy it is not possible to definitively determine that diamond 301 issynthetic via this test is due to HPHT-enhanced diamonds and a fewnatural ‘Type’ diamonds. HPHT-enhanced diamonds are diamonds whichundergo a High Pressure High Temperature (HPHT) process. The HPHTprocess will change the color of the diamonds, for example from brownishdiamonds to colorless diamonds, or from faint yellow diamonds to yellowfancy diamonds. Despite the change in color, HPHT-enhanced diamondsallow ultraviolet light through as the HPHT-enhanced diamond is natural.Besides that, all Type II natural diamonds and very rare Type IaBnatural diamonds also allow ultraviolet light to pass through. Theamount of Type II natural diamonds and Type IaB is very low around 2%.For this reason, the fact that diamond 301 allows ultraviolet lightthrough (such that second photodiode 103 detects it) does notdefinitively conclude that diamond 301 is synthetic. Preferably,processor unit 110 displays on display module 112 the results of thedetermination i.e. that the diamond is possibly synthetic.

FIG. 6 shows a further embodiment, which is similar to the embodiment ofFIG. 3 and FIG. 7 shows a further embodiment, which is similar to theembodiment of FIG. 5. For the sake of brevity, the description of FIGS.3 and 5 is not repeated here.

It should further be appreciated that the exemplary embodiments are onlyexamples, and are not intended to limit the scope, applicability,operation, or configuration of the invention in any way. Rather, theforegoing detailed description will provide those skilled in the artwith a convenient road map for implementing an exemplary embodiment ofthe invention, it being understood that various changes may be made inthe function and arrangement of elements and method of operationdescribed in an exemplary embodiment without departing from the scope ofthe invention as set forth in the appended claims.

The embodiments can also be described with the following lists ofelements being organized into items. The respective combinations offeatures which are disclosed in the item list are regarded asindependent subject matter, respectively, that can also be combined withother features of the application

-   1. A diamond identification apparatus comprising:

a support platform for receiving a gemstone at an observation position;

a first light source arranged to emit light at a predetermined angletowards the observation position;

a first photodiode arranged to detect an amount of light from the firstlight source being reflected from the gemstone at the observationposition;

a second light source arranged to emit light towards the observationposition;

a second photodiode arranged to detect light from the second lightsource that passes through the gemstone at the observation position; and

a processor unit;

wherein the processor unit is configured to:

determine that the gemstone is a diamond in response to the amount oflight detected by the first photodiode;

and if the gemstone is determined to be a diamond, then determine thatthe diamond is natural in response to the second photodiode notdetecting light.

-   2. The diamond identification apparatus of item 1 wherein the    processor unit is further configured to determine that the diamond    is possibly synthetic in response to the second photodiode detecting    light.-   3. The diamond identification apparatus of item 1 or item 2, wherein    the processor unit determines that the gemstone is a diamond by    calculating a reflectivity value in response to the amount of light    detected by the first photodiode, and cross-referencing the    reflectivity value with reference data.-   4. The diamond identification apparatus of item 3, wherein the    reflectivity value is substantially 17.1%, or substantially 19%, or    within the range of 17.1% and 19%.-   5. The diamond identification apparatus of any one of the preceding    items wherein the second photodiode has a horizontal axis and a    vertical axis; and wherein the first light source and the first    photodiode are arranged such that:

the first light source and the first photodiode lie substantially alongthe horizontal axis of the second photodiode and sandwich the secondphotodiode; and

the first light source and the first photodiode do not lie substantiallyalong the vertical axis of the second photodiode.

-   6. The diamond identification apparatus of any one of the preceding    items wherein the first light source, the first photodiode and the    second photodiode form part of a sensor module.-   7. The diamond identification apparatus of any one of the preceding    items wherein the support platform defines an opening for receiving    the gemstone at the observation position.-   8. The diamond identification apparatus of item 7 wherein the    opening of the support platform and the second light source are    arranged to lie substantially along the vertical axis of the second    photodiode.-   9. The diamond identification apparatus of any one of the preceding    items wherein the light emitted by the first light source is visible    or infrared light.-   10. The diamond identification apparatus of any one of the preceding    items wherein the light emitted by the second light source is    ultraviolet light.-   11. The diamond identification apparatus of item 10 wherein the    ultraviolet light emitted by the second light source has a    wavelength of less than 370 nanometers.-   12. The diamond identification apparatus of any one of the preceding    items wherein the first photodiode is oriented towards the    observation position at substantially the predetermined angle.-   13. The diamond identification apparatus of any one of the preceding    items wherein the predetermined angle is between 30° to 60°.-   14. The diamond identification apparatus of any one of items 3 to 13    further comprising a memory module and wherein the memory module    stores the reference data.-   15. The diamond identification apparatus of any one of items 2 to 14    further comprising a display module, and wherein the determination    by the processor unit that the gemstone is a diamond, and the    determination by the processor unit that the diamond is natural or    possibly synthetic, are displayed on the display module.-   16. The diamond identification apparatus of any one of the preceding    items further comprising a housing for encapsulating the support    platform, the first light source, the first photodiode, the second    light source and the second photodiode; the housing comprising a    window which can be opened to insert or remove the gemstone.-   17. A sensor module for use in a diamond identification apparatus,    the diamond identification apparatus comprising a processor unit, a    support platform for receiving a gemstone at an observation position    and a second light source arranged to emit light towards the    observation position, the sensor module comprising:

a first light source arranged to emit light at a predetermined angletowards the observation position;

a first photodiode arranged to detect an amount of light from the firstlight source being reflected from the gemstone at the observationposition; and

a second photodiode arranged to detect light from the second lightsource that passes through the gemstone at the observation position;wherein the processor unit is configured to:

determine that the gemstone is a diamond in response to the amount oflight detected by the first photodiode;

and if the gemstone is determined to be a diamond, then determine thatthe diamond is natural in response to the second photodiode notdetecting light.

-   18. The sensor module of item 17 wherein the second photodiode    detects light and the processor unit determines that the diamond is    possibly synthetic.-   19. The sensor module of item 17 or item 18 wherein the second    photodiode has a horizontal axis and a vertical axis; and wherein    the first light source and the first photodiode are arranged such    that:

the first light source and the first photodiode lie substantially alongthe horizontal axis of the second photodiode and sandwich the secondphotodiode; and

the first light source and the first photodiode do not lie substantiallyalong the vertical axis of the second photodiode.

-   20. The sensor module of any one of items 17 to 19 wherein the light    emitted by the first light source is visible or infrared light.-   21. The sensor module of any one of items 17 to 20 wherein the first    photodiode is oriented towards the observation position at    substantially the predetermined angle.-   22. The sensor module of any one of items 17 to 21 wherein the    predetermined angle is between 30° to 60°.

The invention claimed is:
 1. A diamond identification apparatuscomprising: a support platform for receiving a gemstone at anobservation position; a first light source arranged to emit light at apredetermined angle towards the observation position; a first photodiodearranged to detect an amount of light from the first light source beingreflected from the gemstone at the observation position; a second lightsource arranged to emit light towards the observation position; a secondphotodiode arranged to detect light from the second light source thatpasses through the gemstone at the observation position; and a processorunit; wherein the processor unit is configured to: determine that thegemstone is a diamond in response to the amount of light detected by thefirst photodiode; and if the gemstone is determined to be a diamond,then determine that the diamond is natural in response to the secondphotodiode not detecting light.
 2. The diamond identification apparatusof claim 1, wherein the processor unit is further configured todetermine that the diamond is possibly synthetic in response to thesecond photodiode detecting light.
 3. The diamond identificationapparatus of claim 1, wherein the processor unit determines that thegemstone is a diamond by calculating a reflectivity value in response tothe amount of light detected by the first photodiode, andcross-referencing the reflectivity value with reference data.
 4. Thediamond identification apparatus of claim 3, wherein the reflectivityvalue is substantially 17.1%, or substantially 19%, or within the rangeof 17.1% and 19%.
 5. The diamond identification apparatus of claim 1,wherein the second photodiode has a horizontal axis and a vertical axis;and wherein the first light source and the first photodiode are arrangedsuch that: the first light source and the first photodiode liesubstantially along the horizontal axis of the second photodiode andsandwich the second photodiode; and the first light source and the firstphotodiode do not lie substantially along the vertical axis of thesecond photodiode.
 6. The diamond identification apparatus of claim 1,wherein the first light source, the first photodiode and the secondphotodiode form part of a sensor module.
 7. The diamond identificationapparatus of claim 1, wherein the support platform defines an openingfor receiving the gemstone at the observation position.
 8. The diamondidentification apparatus of claim 7, wherein the opening of the supportplatform and the second light source are arranged to lie substantiallyalong the vertical axis of the second photodiode.
 9. The diamondidentification apparatus of claim 1, wherein the light emitted by thefirst light source is visible or infrared light.
 10. The diamondidentification apparatus of claim 1, wherein the light emitted by thesecond light source is ultraviolet light.
 11. The diamond identificationapparatus of claim 10, wherein the ultraviolet light emitted by thesecond light source has a wavelength of less than 370 nanometers. 12.The diamond identification apparatus of claim 1, wherein the firstphotodiode is oriented towards the observation position at substantiallythe predetermined angle.
 13. The diamond identification apparatus ofclaim 1, wherein the predetermined angle is between 30° to 60°.
 14. Thediamond identification apparatus of claim 3, further comprising a memorymodule and wherein the memory module stores the reference data.
 15. Thediamond identification apparatus of claim 2, further comprising adisplay module, and wherein the determination by the processor unit thatthe gemstone is a diamond, and the determination by the processor unitthat the diamond is natural or possibly synthetic, are displayed on thedisplay module.
 16. The diamond identification apparatus of claim 1,further comprising a housing for encapsulating the support platform, thefirst light source, the first photodiode, the second light source andthe second photodiode; the housing comprising a window which can beopened to insert or remove the gemstone.
 17. A sensor module for use ina diamond identification apparatus, the diamond identification apparatuscomprising a processor unit, a support platform for receiving a gemstoneat an observation position and a second light source arranged to emitlight towards the observation position, the sensor module comprising: afirst light source arranged to emit light at a predetermined angletowards the observation position; a first photodiode arranged to detectan amount of light from the first light source being reflected from thegemstone at the observation position; and a second photodiode arrangedto detect light from the second light source that passes through thegemstone at the observation position; wherein the processor unit isconfigured to: determine that the gemstone is a diamond in response tothe amount of light detected by the first photodiode; and if thegemstone is determined to be a diamond, then determine that the diamondis natural in response to the second photodiode not detecting light. 18.The sensor module of claim 17, wherein the second photodiode detectslight and the processor unit determines that the diamond is possiblysynthetic.
 19. The sensor module of claim 17, wherein the secondphotodiode has a horizontal axis and a vertical axis; and wherein thefirst light source and the first photodiode are arranged such that: thefirst light source and the first photodiode lie substantially along thehorizontal axis of the second photodiode and sandwich the secondphotodiode; and the first light source and the first photodiode do notlie substantially along the vertical axis of the second photodiode. 20.The sensor module of claim 17, wherein the light emitted by the firstlight source is visible or infrared light.
 21. The sensor module ofclaim 17, wherein the first photodiode is oriented towards theobservation position at substantially the predetermined angle.
 22. Thesensor module of claim 17, wherein the predetermined angle is between30° to 60°.